FROM THIS EPISODE

Social media have been a force for liberation in repressive countries. They've also been used to organize crime. Can governments control Facebook, Twitter and other networks, and protect free speech at the same time? Also, the United States calls for Syrian President Assad to step down, and Standard & Poor's faces a federal investigation.

Banner image: A demonstrator wears a mask as he tries to use his cell phone during a protest inside the Bay Area Rapid Transit (BART) Civic Center station on August 15, 2011 in San Francisco, California. Photo by Justin Sullivan/Getty Images

After weeks of brutal government violence in Syria, the leaders of Britain, France, Germany, the European Union and the United States called today for President Bashar al-Assad to step down. Affirming that the people of Syria "deserve a government that respects their dignity, protects their rights and lives up to their aspirations," Secretary of State Hilary Clinton said that it was time for Assad to "leave the transition to the Syrians themselves." Steven Lee Myers reports on the State Department for the New York Times.

Facebook, Twitter and other social media have allowed Egyptians, Iranians, Chinese and others to challenge repressive governments. The governments, in turn, have been criticized for shutting the media down. Now countries with traditions of protecting free speech face a different challenge. Recent incidents, from London to San Francisco, have led to crackdowns, including prior restraint in the name of law and order. When social media are used to advocate violence, organize riots or coordinate crime, can government block access to the perpetrators and others as well? Will there be new limitations on the right to free speech as the law catches up with the technology?

When Standard & Poor's downgraded America's credit rating, questions were raised about the agency's role in failing to blow the whistle on sub-prime mortgages. Now the Justice Department has launched an investigation of America's largest credit rating agency. At the same time, local governments are taking another look at whether S&P is serving their needs. Louise Story, who broke the news last night in the New York Times, has more on the investigation and on the ripple effect of the federal downgrade.